- vsnet-campaign-dn - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-campaign-dn 17524] KKO observations of asassn-25bx, -25ca
by Berto Monard 28 May '25

28 May '25

no modulation (yet)

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[vsnet-campaign-dn 17523] ASASSN-25bz: new SU UMa-type dwarf nova
by Yusuke Tampo 28 May '25

28 May '25

ASASSN-25bz: new SU UMa-type dwarf nova ASASSN-25bz (=AT 2025lkr) was discovered at 14.8 mag on 20 May by ASAS-SN. The suggested outburst amplitude is ~8 mag according to the VSX. ASAS-SN reported to the TNS that this could be a classical nova based on its low Galactic latitude b~-2.0 deg. https://www.aavso.org/vsx/index.php?view=detail.top&oid=10848672 I obtained the time-resolved observations of ASASSN-25bz with the SAAO/Lesedi telescope on 26 and 27 May. Its light curve shows a prominent ordinary superhump with an amplitude of 0.15 mag and a period of ~0.0561(1) d (1-d aliases are possible). The optical spectrum obtained on 23 May with the SAAO/Lesedi telescope is dominated by Balmer absorption lines. Thus, I conclude that ASASSN-25bz is a new SU UMa-type dwarf nova. The system is around 15.6 mag. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17521] TCP J18513997+3522412: large-amplitude modulation, possibly eclipsing WZ Sge-type dwarf nova?
by Yusuke Tampo 27 May '25

27 May '25

TCP J18513997+3522412: large-amplitude modulation, possibly eclipsing WZ Sge-type dwarf nova? TCP J18513997+3522412 was discovered by Y. Nakamura on 22nd May at 13.7 mag (unfiltered). The counterpart star in Pan-STARRS1 is r~20.5 mag, and thus the outburst amplitude is 6.8 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J18513997+3522412.html https://www.aavso.org/vsx/index.php?view=detail.top&oid=10848644 Sano-san reported the time-resolved observations of this object. Although the baseline was just one hour, the light curve shows a large-amplitude modulation of ~0.35 mag. This is likely either an ordinary superhump in a SU UMa-type dwarf nova or even a large-amplitude early superhump + eclipse in an eclipsing WZ Sge-type dwarf nova. Further time-resolved observations with longer baselines are encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17520] TCP J02472889+6758170 = Gaia DR3 517539710877791488
by Yusuke Tampo 26 May '25

26 May '25

TCP J02472889+6758170 = Gaia DR3 517539710877791488 The NMW team discovered this transient at 13.0 mag (unfiltered), which is associated with the known variable star Gaia DR3 517539710877791488 with ~18.0 mag. They suggest that this could be an AM CVn star in outburst. Its blue color in the Pan-STARRS1 image also supports this suggestion, and TCP J02472889+6758170 is at least a CV in new outburst. http://www.cbat.eps.harvard.edu/unconf/followups/J02472889+6758170.html https://www.aavso.org/vsx/index.php?view=detail.top&oid=2841325 Time-resoved observations are encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17519] ASASSN-25bu: new SU UMa-type dwarf nova
by Yusuke Tampo 23 May '25

23 May '25

ASASSN-25bu: new SU UMa-type dwarf nova ASASSN-25b was discovered by ASAS-SN on 2025-05-12.06. The outburst amplitude is ~8.3 mag according to the VSX. This object is currently ~17.5 mag. https://www.aavso.org/vsx/index.php?view=detail.top&oid=10848624 Josch Hambsch and the SAAO team have reported the time-seeries observations of ASASSN-25bu. Lesedi/Mookodi observations on 22 May showed probable superhumps with a period of ~0.0574 d and an amplitude of ~0.15 mag. Thus ASASSN-25bu is a new SU UMa-type dwarf nova. Considering its short superhump period, large outburst amplitude, and no previous outbursts, ASASSN-25bu might be a WZ Sge-type. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17517] ZTF18acynctq = TCP J20402089+4915562 = ASASSN-25bt: new SU UMa star candidate
by Yusuke Tampo 20 May '25

20 May '25

ZTF18acynctq = TCP J20402089+4915562 = ASASSN-25bt: new SU UMa star candidate XOSS team via TOCP/TNS and ASAS-SN reported the 2025 outburst of this system, which is already known as ZTF18acynctq in its 2018 outburst. https://alerce.online/object/ZTF18acynctq http://www.cbat.eps.harvard.edu/unconf/followups/J20402089+4915562.html https://www.aavso.org/vsx/index.php?view=detail.top&oid=10848612 Its 2018 outburst lasted for ~15 days and showed a possible rebrightening in the ATLAS data. Thus the outburst cycle is ~2300 d. This system is currently ~16.0 mag, and time-resolved observations may detect superhumps. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17516] TCP J19065629+4019093: new SU UMa-type dwarf novae and WZ Sge-type candidate
by Yusuke Tampo 11 May '25

11 May '25

TCP J19065629+4019093: new SU UMa-type dwarf novae and WZ Sge-type candidate TCP J19065629+4019093 was discovered by Y. Nakamura on 29th April, 2025, at 13.1 mag. S. M. Brincat, J. Hambsch, Itoh-san, T. Tordai, and Sano-san have reported the time-resolved observations of this new transient. The latest time-resolved observations on 9th May by S. M. Brincat report the presence of single-peaked superhumps with ~0.056 d. Thus TCP J19065629+4019093 is a new SU UMa-type dwarf nova. Taking into account this late (~10 d) appearance of superhumps, TCP J19065629+4019093 is likely a face-on WZ Sge-type dwarf nova. Further observations are encouraged to determine its superhump period. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17515] TCP J13560585+3727068: new WZ Sge-type dwarf nova
by Yusuke Tampo 30 Apr '25

30 Apr '25

TCP J13560585+3727068: new WZ Sge-type dwarf nova TCP J13560585+3727068 was discovered on 2025 04 26.7039 (UTC) at 14.3 mag (unfiltered). GIven the possible counterpart of Gaia G~20.8 and peak in ASAS-SN around 13.5 mag on 2025 04 24, the outburst amplitude is ~7.3 mag Itoh-san reported the time-resolved observations of TCP J13560585+3727068 on 2024 04 28 and 29. The light curve shows double-peaked modulations with the tentative period is 0.0574(1) d (aliases are possible) with ~0.04-mag amplitude. Thus, TCP J13560585+3727068 is likely a new WZ Sge-type dwarf nova. http://www.cbat.eps.harvard.edu/unconf/followups/J13560585+3727068.html https://asas-sn.osu.edu/sky-patrol/coordinate/19dd78d4-1819-43b4-bb38-be83e… Time-resolved observations are encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17512] TCP J08374922+0134065: new WZ Sge-type dwarf nova with large early superhump amplitude
by Yusuke Tampo 14 Apr '25

14 Apr '25

TCP J08374922+0134065: new WZ Sge-type dwarf nova with large early superhump amplitude TCP J08374922+0134065 was discovered by Y. Nakamura on 3rd April at 14.7 mag. Based on the suggested counterpart (GALEX J083749.2+013407) with g=20.22(2) and the brightest ASAS-SN measurement with g~13.4 mag, the outburst amplitude is 6.8mag. http://www.cbat.eps.harvard.edu/unconf/followups/J08374922+0134065.html https://asas-sn.osu.edu/sky-patrol/coordinate/dce846f3-485d-4614-bace-a8b3e… Itoh-san has reported the time-resolved observations on 6th April and the light curve shows a double-peaked modulation with a period of ~0.059 d and an amplitude of 0.2 mag with possible eclipses. Thus TCP J08374922+0134065 is a new WZ Sge-type dwarf nova with high inclination. Time-resolved observations are strongly encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17511] TCP J06455595+1210577: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 02 Apr '25

02 Apr '25

Dear colleagues, I have just completed the analysis of my unfiltered CCD observations of TCP J06455595+1210577, obtained on Apr 01/02, 2025 at CBA Belgium Observatory. The data was collected using a 0.40-m f/10.0 telescope and QHY-268M CMOS camera under clear skies. This object was recently discovered by XOSS and announced as a possible CV candidate (see http://www.cbat.eps.harvard.edu/unconf/followups/J06455595+1210577.html) The light curve clearly reveals the presence of regular superhumps with an amplitude of 0.29 mag, establishing TCP J06455595+1210577 as a new SU UMa-type dwarf nova. A period analysis, using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0731 +/- 0.0014d. The object was measured at mag CV = 16.2 on Apr 01st. Image calibration and photometry were performed using Phoranso, allowing me to simultaneously measure 4 other variables within the field of view of TCP J06455595+1210577. Further observations are encouraged to refine the superhump period. I will submit my observations to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m PERANSO : The Light Curve and Period Analysis Software http://www.peranso.co <http://www.peranso.com/> m PHORANSO: Photometric Reduction and Analysis Software http://www.phoranso.com <http://www.phoranso.com/>

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